RNAi screens for genes required by MLL-AF9^pos AML cell lines. (A) Schematic of RNAi screens. Numbers in circles indicate genes scoring as positive. Genes scoring exclusively in MLL-AF9^pos AML cell lines are indicated in red. (B) Candidate genes preferentially required in MLL-AF9^pos AML cell lines. For each of the top-ranking genes, the shRNAs scoring in NOMO-1 and/or THP-1 are shown. Negative B-scores indicate reduced viable cell numbers. (C) Validation of candidate genes. Shown are the effects of 2 shRNAs per candidate gene on cell viability and proliferation of AML cell lines with and without an MLL-AF9 fusion and the knockdown efficiency of each shRNA in NOMO-1 cells, as determined by qRT-PCR.